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Morphology and habit of some Odontites species. A, Odontites luteus (France). B, Odontites luteus (left) and O. viscosus (right; France). C, Odontites viscosus (Morocco). D, Odontites vernus/vulgaris (France). E, Odontites jaubertianus (France). F, Odontites maroccanus (Morocco). G, Odontites viscosus population (France). H, Odontites maroccanus (Morocco). I, Odontites corsicus (Corsica, France). J, Odontites luteus population (France). K, Odontites powellii (Morocco). Photos: M. Gaudeul, except C, D, H, I, K by G. Rouhan.
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Premise of research. Odontites is an herbaceous genus composed of 27 species, mostly distributed around the Mediterranean Basin. As a first step toward studying species diversification within this genus, our goals were to (i) test previous hypotheses about phylogenetic relationships among species; (ii) assess whether the closely related genera Bart...
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... genus Odontites Ludw. comprises 27 hemiparasitic, usu- ally herbaceous and annual species (Bolliger 1996;Crespo and Mateo Sanz 2009). Species are distributed along both the north- ern and the southern shores of the Mediterranean Sea, on islands such as Corsica and Sicily, and some of them extend northward up to Scandinavia, westward to the island of Madeira, and east- ward to the Himalayas. Species differ by their distribution range (from widely distributed to microendemics) and display a vari- ety of morphological, phenological, and life-history traits, such as flowering time (spring vs. autumn; fig. 1; illustrations in Bolliger 1996). A previous study based on chloroplast DNA se- quencing and phylogenetic reconstructions showed that the ge- nus diversified recently (mostly !10 Ma; Gaudeul et al. 2016), probably explaining the low resolution in some clades. Such a low resolution may also be due to reticulate evolution, which was previously suggested in Odontites based on morphology and karyology: O. vernus has been hypothesized to be an auto- tetraploid of O. vulgaris, while O. jaubertianus was thought to be an allotetraploid of O. vulgaris and O. luteus (Bolliger 1996 and references therein). The reconstruction of both plastid-and nuclear-based phylogenetic relationships sometimes allows the identification of incongruent patterns among them, which can suggest reticulate events (Linder and Rieseberg 2004; Seehau- sen 2004; Vriesendorp and Bakker 2005 and references therein; Soltis et al. 2008; for examples, see also, e.g., Frajman and Oxelman 2007;Yi et al. 2008;Wu et al. 2015). Another expla- nation for such incongruences is incomplete lineage sorting of ancestral polymorphisms, and it is often difficult to discrimi- nate between reticulate evolution and incomplete lineage sort- ing based on DNA sequences (see, e.g., Van der Niet and Linder 2008; Blanco-Pastor et al. 2012). In Odontites, some ambigui- ties also remain on the circumscription of the genus and the in- clusion of four closely related genera that were recently segre- gated from Odontites based on morphology (Bolliger 1996): Bartsiella Bolliger, Bornmuellerantha Rothm., Macrosyringion Rothm., and Odontitella Rothm. These four genera count a to- tal of six species (Bolliger 1996;Dönmez and Mutlu 2010). Pre- vious phylogenetic investigations focused on the Rhinantheae tribe ( Tesitel et al. 2010;Scheunert et al. 2012) but included only a few Odontites species (at most, six out of 27 in Scheunert et al. 2012). Scheunert et al. (2012) and Gaudeul et al. (2016) suggested the need to consider a broadly circumscribed Odon- tites s.l. genus, including Bartsiella and Bornmuellerantha (as also shown by Tesitel et al. 2010 for the latter one). They con- firmed Odontitella as a distinct lineage, whereas the position of Macrosyringion remained ambiguous, with an incongruence between the topologies based on nuclear DNA (nDNA) and chloroplast DNA ...
Citations
... Species delimitation is thus based on the observation of qualitative or quantitative diagnostic characters showing scarce or no overlap among the studied taxonomic units (Wiens, 2007). However, morphology alone can be deceptive and can lead scholars to arrive at conclusions that do not reflect the actual relationships among taxa (Bateman, 2018;Gaudeul et al., 2018;Liu et al., 2022). Despite this, a great number of species are still accepted nowadays based only on qualitative morphological description (Rouhan & Gaudeul, 2014). ...
Santolina is a clear example of a genus lying in an alpha-taxonomic status, with species accepted only based on qualitative morphological descriptions. In particular, taxonomic issues still need to be resolved for Santolina populations from southern France and north-eastern Spain, so that we carried out an integrative taxonomic study involving morphometrics, cypsela morphometrics, niche overlap, and phylogenetic analysis
based on six plastid markers (trnH-psbA, trnL-trnF, trnQ-rps16, rps15-ycf1, psbM-trnD, and trnS-trnG). Our results revealed that the current taxonomic circumscription is not adequate. In particular, the Santolina populations at the foothills of eastern Pyrenees, previously included in the variability of S. benthamiana, have to be considered as a distinct species, namely S. intricata. In addition, despite their high phylogenetic relatedness, S. benthamiana s.str. and S. ericoides can be still considered as distinct species due to clear morphological and ecological differentiation. Finally, we demonstrated that three different subspecies can be recognized in S. decumbens, a species endemic to Provence. For one of these subspecies, due to its extremely restricted distribution range, conservation issues are pointed out.
... Our understanding of the phylogenetic relationships among major clades of Orobanche [17][18][19], along with species-level relationships, have been greatly advanced by studying molecular data [20][21][22]. ...
A species of Orobanche was observed on spiny cocklebur (Xanthium spinosum) for the first time in Iran and tentatively was named IR-Iso.This study was conducted to make a phylogenetic analysis of the Orobanche using 5.8S rRNA region sequences, and also to better understand its sequence pattern. The full-length ITS1-ITS2 region of the new Orobanche isolate was PCR-amplified from the holoparasitic plant parasitizing X. spinosum. Sequences of the amplicons from the isolate were 100% identical but differed by 5.6–6.7% from most homologous GenBank accessions to 37.9% divergence from distant species. The analysis of the molecular variance showed that variation between-population (61.9%, SE = 0.04) was larger than within-population. Neighbor-joining analysis placed the Iranian isolate in the same clade as most of the Orobanche and Phelipanche species. The isolate was more closely related to Orobanche aegyptiaca (from China), and this was confirmed by using a structure analysis. However, complementary analyses showed that the Iranian isolate has a unique nucleotide substitution pattern, and hence it was considered as an ecotype of O. aegyptiaca (ecotype Alborzica). In this paper we report on the association between this new ecotype of Orobanche and X. spinosum.
... In that chapter, the phylogenetic relationships of the various clades in the family were discussed, and five disconnected phylogenetic trees were shown that included lists of unplaced taxa based on their assumed affinity. Although there have been numerous phylogenetic studies since 2013 (e.g., Schneider & al., 2016;Uribe-Convers & Tank, 2016;Fu & al., 2017;Pinto-Carrasco & al., 2017;Gaudeul & al., 2018;Yu & al., 2018;Li & al., 2019), most have been focused on a particular group (tribe) within Orobanchaceae. It appears that there does not exist in the literature an attempt to incorporate all the available phylogenetic information to produce a "super tree" of Orobanchaceae. ...
... The topology for Rhinantheae (Fig. 4) for the most part follows Pinto-Carrasco & al. (2017); however, other studies offered different interpretations of generic boundaries based on different molecular analyses (e.g., Těšitel & al., 2010;Scheunert & al., 2012;Uribe-Convers & Tank, 2016;Gaudeul & al., 2018). Melampyrum L. is sister to the rest of the clade, a result seen in all molecular analyses. ...
... These changes left Bartsia monospecific, i.e., B. alpina L., which is found in Arcticalpine Europe and northeastern North America. Pinto-Carrasco & al. (2017) and Gaudeul & al. (2018) agreed on the merger of Bartsiella Bolliger and Bornmuellerantha Rothm. with Odontites Ludw. ...
Angiosperms that morphologically and physiologically attach to other flowering plants by means of a haustorium have evolved 12 times independently resulting in 292 genera and ca. 4750 species. Although hemiparasites predominate, holoparasitism has evolved in all but two clades, Cassytha (Lauraceae) and Krameria (Krameriaceae). Santalales contains the largest number of genera (179) and species (2428) among the 12 parasitic plant lineages whereas Orobanchaceae is the largest single family with 102 genera and over 2100 species. This review presents the current state of knowledge on the molecular phylogenetic relationships among all clades of parasitic angiosperms. These methods have been particularly important in revealing the closest non‐parasitic relatives of holoparasites, plants that exhibit reduced morphologies, increased substitution rates, and frequent horizontal gene transfers, all of which confound phylogenetics. Although comprehensive molecular phylogenies are still lacking for many of the large genera, nearly complete generic level sampling exists, thus allowing unprecedented understanding of the evolutionary relationships within and among these fascinating plants.
... Specifically, we want to solve remaining uncertainties concerning (i) the unclear positions of Brandisia and the Cymbaria-Siphonostegia clade, (ii) the ambiguous support for monophyly of the Orobanche clade, and (iii) the contradicting relationships among the Castilleja-Pedicularis clade, the Euphrasia-Rhinanthus clade, and the Striga-Alectra clade inferred previously (Bennett and Mathews, 2006;McNeal et al., 2013). Additionally, we also want to assess the suitability of these markers at lower taxonomic levels using Odontites (from the Euphrasia-Rhinanthus clade), where recent phylogenetic work has revealed strong discrepancies among markers (Pinto-Carrasco et al., 2017;Gaudeul et al., 2018). ...
Molecular phylogenetic analyses have greatly advanced our understanding of phylogenetic relationships in Orobanchaceae, a model system to study parasitism in angiosperms. As members of this group may lack some genes widely used for phylogenetic analysis and exhibit varying degrees of accelerated base substitution in other genes, relationships among major clades identified previously remain contentious. To improve inferences of phylogenetic relationships in Orobanchaceae, we used two pentatricopeptide repeat (PPR) and three low-copy nuclear (LCN) genes, two of which have been developed for this study. Resolving power and level of support strongly differed among markers. Despite considerable incongruence among newly and previously sequenced markers, monophyly of major clades identified in previous studies was confirmed and, especially in analyses of concatenated data, strongly supported after the exclusion of a small group of East Asian genera (Pterygiella and Phtheirospermum) from the Euphrasia-Rhinanthus clade. The position of the Orobanche clade sister to all other parasitic Orobanchaceae may indicate that the shift to holoparasitism occurred early in the evolution of the family. Although well supported in analyses of concatenated data comprising ten loci (five newly and five previously sequenced), relationships among major clades, most prominently the Striga-Alectra clade, the Euphrasia-Rhinanthus clade, and the Castilleja-Pedicularis clade, were uncertain because of strongly supported incongruence also among well-resolving loci. Despite the limitations of using a few selected loci, congruence among markers with respect to circumscription of major clades of Orobanchaceae renders those frameworks for detailed, species-level, phylogenetic studies.
The western Eurasian-Mediterranean grass genus Cynosurus, comprising about 11 species, is morphologically well delimited by the regular occurrence of conspicuous sterile spikelets distal to the fertile ones on the outer, abaxial side of the inflorescences. However, our molecular phylogenetic study using nuclear ribosomal DNA (ITS, ETS) and plastid DNA sequences (trnL–F, matK) has shown that the genus is not monophyletic in its current delimitation, but consists of three distinct lineages. These lineages were found to be closely related to a group of 6–7 genera taxonomically assigned to the subtribe Parapholiinae. These Parapholiinae genera were consistently monophyletic in our analyses, but the suggested relationships to the three lineages of Cynosurus varied depending on the particular DNA region examined. This was the case for both plastid and nuclear DNA, with cytonuclear discordance and ‘chloroplast capture’ indicating earlier hybridization. Interestingly, hybridization also proved to be the most likely explanation even with regard to the 18S–26S cistrons of the nuclear ribosomal DNA, where an exceptional evolutionary divergence between ITS and ETS was found. The results highlight and illustrate the important role of hybridization in the evolution of grasses. In terms of taxonomy, our findings argue against maintaining a polyphyletic genus Cynosurus s.l. but instead argue for dividing it into three monophyletic genera: Cynosurus s.s., Falona, which is reestablished here, and Ciliochloa, which is described as a new genus. In addition, it is proposed that the two subtribes Cynosurinae and Parapholiinae be combined into a single subtribe Cynosurinae, which is also monophyletic. The possible genetic background of the formation of sterile spikelets and the occasional occurrence of inflorescences with consistently fertile spikelets are discussed. New combinations are Ciliochloa effusa, C. effusa var. obliquata, C. effusa var. fertilis, C. elegans, C. gracilis, C. turcomanica and Falona colorata.
Premise: It has been repeatedly shown that the remarkable variation of the genome
size of angiosperms can be shaped by extrinsic selective pressures, including nutrient
availability. Carnivory has evolved independently in ten angiosperm clades, but all
carnivorous plants share a common affinity to nutrient-poor habitats. As such, carnivory
and genome reduction could be responses to the same environmental pressure.
Indeed, the smallest genomes among flowering plants are found in the carnivorous
family Lentibulariaceae, where a unique mutation in cytochrome oxydase c (COX) is
suspected to promote genome miniaturization. Despite these hypotheses, a
phylogenetically informed test of genome size and nutrient availability across
carnivorous clades has so far been missing.
Methods: Using linear mixed models, we compare genome sizes of 127 carnivorous
plants from 7 diverse angiosperm clades with 1072 of their non-carnivorous relatives;
we also test whether genome size in Lentibulariaceae reflects the possession of the
COX mutation.
Results: The genome sizes of carnivorous plants do not differ significantly from those
of their non-carnivorous relatives. Based on available data, no significant association
between the COX-mutation and genome miniaturization could be confirmed, not even
when considering polyploidy.
Conclusions: Carnivory alone does not seem to significantly affect genome size
decrease. It is plausible that it actually counterbalances the effect of nutrient limitation
on genome size evolution. The role of COX-mutation in genome miniaturization needs
to be evaluated by analysis of a broader dataset, because current knowledge of its
presence across Lentibulariaceae covers less than 10 % of species diversity in this
family.
